John Tristan, Count of Valois French prince (1250–1270) Parents Margaret of Provence Louis IX of France Children Siblings Philip III of France Peter, Count of Perche and Alençon Robert Agnes of France, Duchess of Burgundy Margaret of France, Duchess of Brabant Blanche of France, Infanta of Castile Louis of France Isabella of France, Queen of Navarre Blanche de France John of France Partners Yolande II, Countess of Nevers